Alright, let's work through 3453 times 6210 step by step
3453 × 6210 = 6210 × (3453)
+ 6210 × 3 what gives us 18630
+ 6210 × 50 that results in 310500
+ 6210 × 400 giving us 2484000
+ 6210 × 3000 what gives us 18630000

= 21443130
